PCL81 Pentode Part

All tube operating points below are by no means definitive good sound recipe for your particulate tube project. Lowest THD point is not necessary best sounding one and there is always some variance even in a NOS tube batch from the same manufacturer!  Below information is only useful as a general starting point and is ment to get you in a ballpark when no measurement equipment is available.

Lowest THD operating point spectrum

29mA, -8V BIAS

Recommended operating point spectrum

40mA, -4V BIAS

Other operating points

 42mA, -3.4V BIAS
29mA, -5V BIAS 

Traced plate curves


Excellent pentode with a clean spectrum. Should be good for a couple of sweet SE wat’s. Single PCL81 amp anyone? Available for sale.

Copyright © 2022 MV Audio Labs. Legal Disclaimer.